私の翻訳：
Somehow I had to talk with my wife and think about how we could improve our situation. However, we could not spend extra money. Therefore, we thought about how the customers needs are different during different times of the day, and how we could increase the rotation speed of customers in and out of the store.

これは、何とかしなければと妻と話しあって、改善策を考えた。
Literally translated, it's: For something must be done, talking with my wife, I thought of improvement plan.
Meaning-wise: Talking with my wife to figure out something (that must be done), we explored an improvement strategy.
何とかしなければと part can be interpreted either way.
a) 私は何とかしなければと考えた → Then, 私は妻と話しあった
b) 私は妻と「何とかしなければ」と考えながら話しあった/(They both thought something must be done and started discussion)
I personally had an impression that (b) is better, meaning-wise. But still, in the Japanese sentence, it has a (slight) nuance that three things happened in a row (in chronological order):
1) I thought that something has to be done
2) I talked with my wife
3) I (we) tried to come up with a good idea
In Japanese, in general, the subject ( I or we ) can be decided by seeing the context. If his wife was sharing the concern before that, the first (1) can be "we thought". If his wife wasn't aware of the problem, it should be "I". Makes sense?

もっとも、金はかけられない。
However, we can’t spend money.

So, you know, they try to focus two things, which are “時間帯による客層違いをはっきりさせること” and “客の回転を速めること” for the sales growth.
客層 means quality of customers. It’s one of the marketing jargon. Something like “what kind of people the customers are?” So 時間帯による客層違い means that the average customer type is different depending on the time of the day. For instance, their customers are mostly young girls in the morning, and they have a lot of elderly customers in the afternoon…
はっきりさせること here means to figure out / clarify (and recognize/grasp), so that they can make a good plan for sales considering the customers’ needs. (maybe by conducting some kind of research)
客の回転 part would be easy. Speeding up the rotation of customers would be good for them.

NileCat strikes again!
Everything is crystal clear! Oh how I've missed your explanations.
I think it really was that first sentence that threw me ... I had a 'general' idea of what it was saying, but I like to to be as specific as possible, and I think you've nailed that down for me.